Vaccination clearly represents one of the most cost effective approaches in preventive medicine. Over the past two decades, new techniques in recombinant DNA and biotechnology offer unprecedented opportunities for the development of new vaccines. Many training opportunities exist to prepare individuals for research in immunology, molecular genetics, infectious diseases, and other specific aspects of vaccine development, but too few training opportunities offer broad exposure to both laboratory and clinical trial aspects of vaccinology. For the past 27 years, the Center for Vaccine Development of the University of Maryland School of Medicine has been involved in all aspects of vaccine development, from basic laboratory studies involving genetic construction of recombinant vaccines to Phase 1 through Phase 4 clinical trials. We propose a formal program in which individuals with M.D. or Ph.D. degrees can be prepared specifically for careers in vaccinology, either to pursue basic vaccine development research or to conduct investigative clinical trials. The number of trainees involved in this training program will be two per year for a total of five years. Support only for years 1 and 2 are requested from this proposal; support for the third and possible fourth years will be generated from fellowships, research grants, or other sources. The training program in vaccinology offers to all trainees a broad exposure to both the laboratory and clinical trial phases of vaccinology. Beyond this broad exposure, the program is set up as two tracks so that each trainee will gain more intensive experience in either the laboratory aspects or the clinical phases of vaccinology, depending upon which track they choose. The Laboratory track will allow the training of basic scientists and physician/scientists in vaccine development laboratory research, particularly in the use of recombinant DNA technology to prepare new vaccine candidates and the use of modern immunological techniques to study the human humoral and cellular immune response to different vaccines. The Clinical track will train clinicians (internists or pediatricians) in clinical trial design, protocol preparation, procurement of administrative and ethical clearances, performance of clinical trials and analysis of data. The ultimate goal of this training program is to provide a well-trained cadre of individuals who can fully exploit the unprecedented opportunities now available in vaccine development.